High-resolution urban-scale impact of retro-reflective façade materials on building thermal loadBizjak, Marko (Avtor) Mongus, Domen (Avtor) Lukač, Niko (Avtor) Yuan, Jihui (Avtor) thermal loadlagre scaleretro-reflective materialsglass beadprismThis paper presents a high-resolution urban-scale evaluation of the impact of retro-reflective (RR)facade materials on building thermal load. Unlike earlier studies limited to isolated buildings or simplified geometries, we integrate LiDAR-derived 3D city models, local meteorological data, and per-triangle thermal load simulation to quantify seasonal thermal load impact on an urban scale. The triangle-based framework enables detailed estimation of shading, orientation, and vegetation effects under realistic urban configurations. The methodology was applied to 914 buildings in Celje, Slovenia, represented by more than seven million building surface triangles. Results show that Prism RR material increased annual heating demands by 2.1 % and reduced cooling demands by 0.76 %, while Glass bead material increased heating by 1.6 % and reduced cooling by 0.65 %. On the days of maximum city-aggregate cooling demand reduction, Prism and Glass bead materials reduced cooling demands by upto 19.31 % and 15.39 %,respectively. These location-specific results demonstrate a seasonal trade-off, where reduced summer cooling demand is counter balanced by increased heating demand. The analysis also identifies a previously underreported seasonal asymmetry, with the highest heating demand increases occurring in spring when solar irradiation is high yet heating demand remains.Springer Nature20252025-12-12 09:39:21Članek v reviji96249UDK: 004.9COBISS_ID: 260140547DOI: 10.1038/s41598-025-30085-3ISSN pri članku: 2045-2322sl© The Author(s) 2025